Spring MVC @ModelAttribute注解的使用

我会带着你远行 2022-05-17 13:34 182阅读 0赞

Spring MVC @ModelAttribute注解只支持一个属性value，类型为String，表示绑定的属性名称。被@ModelAttribute注解的方法会在Controller每个方法执行前被执行。

创建UserController

package com.controller;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    @Controller
    public class UserController {
    	/**
    	 * 被@ModelAttribute注解的userModel方法会先于login调用，它把请求参数userName
    	 * 的值赋给userName变量，并设置了一个属性userName到Model中，而属性的值就是userName变量的值
    	 * @param userName
    	 * @return
    	 */
    	@ModelAttribute("userName")
    	public String userModel(@RequestParam("userName")String userName) {
    		return userName;
    	}
    	@RequestMapping("/login")
    	public String login() {
    		return "success";
    	}
    }

创建index.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
        pageEncoding="utf-8"%>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="utf-8">
    <title>index</title>
    </head>
    <body>
    	<h4>测试@ModelAttribute</h4>
    	<form action="login" method="post">
    		<table>
    			<tr>
    				<td>用户名:</td>
    				<td><input type="text" name="userName"></td>
    			</tr>
    			<tr>
    				<td></td>
    				<td><input type="submit" value="登录"></td>
    			</tr>
    		</table>
    	</form>
    </body>
    </html>

创建success.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"
        pageEncoding="utf-8"%>
    <%@taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
    <!DOCTYPE html>
    <html>
    <head>
    <meta charset="utf-8">
    <title>success</title>
    </head>
    <body>
    	用户名:${requestScope.userName }
    </body>
    </html>

启动Tomcat访问index.jsp

![70][]

输入用户名，点击【登录】

![70 1][]

[70]: /images/20220517/afa546fab7ea442f95ff1ce1bd8e7449.png
[70 1]: /images/20220517/26b6b0252398424298e87332ea5595dd.png